A widely used type of refrigeration compressor consists of a motor-compressor assembly having a vertical shaft, the motor being at the top and the assembly being enclosed in a hermetically sealed container or "shell". It is common to provide for protection against burnout of the electric motor by means of a thermally responsive protector which interrupts the motor circuit in the event of overheating. It has long been recognized as desirable to mount the protector appurtenant to the end turns of the stator winding of the motor, since this area heats quickly in event of an overload. Various protector mounting arrangements have been employed in an effort to achieve maximum efficiency while minimizing disadvantageous factors. In assembling such motor compressors, the motor stator is positioned on top of and bolted to the frame of the compressor. The air gap between the armature and stator is adjusted and fixed during assembly of the unit, then the bolts or machine screws which hold the stator in such position are tightened. Thereafter the shims are of course removed. For reasons connected with the operation of the refrigeration system, modern units of the indicated character also incorporate a sheet metal shroud or cover secured to the upper end of the motor within the shell, overlying the end turns and the protector. It is advantageous to secure such shroud or cover by means of the same screws or bolts which are used to secure the stator to the frame, not only for the sake of economy, but because the bolts or screws which secure the stator are heavy, well-secured, and virtually free of any possibility of breakage or loosening under the recurrent vibration encountered during the long service life expected of these units.
Inasmuch as the protector must be installed before the internal motor cover or shroud is applied, difficulty has been encountered in mounting the protector in the most advantageous position, and thereafter securing the shroud, without disturbing the air gap and without resorting to a plurality of smaller separate screws or fasteners for the cover. The overall objective of the present invention is to provide an improved system for mounting such a thermal protector and motor cover or shroud in a compressor unit of the indicated type. A related object is to provide such an improved mounting system which can be quickly and easily installed, and supported in a positive manner, after the gap between the rotor and stator of the motor has been adjusted and the stator has been permanently fixed in position. Another related object is to provide such an improved mounting means which reduces labor costs and minimizes the danger of improper installation by virtue of the fact that the protector unit and its supporting means can be easily, quickly and positively locked in place by the simple act of pushing the motor cover into position. A further object resides in the provisions of a protector retainer which will accomodate a number of different types of protectors.
Other objects and advantages will become apparent to persons skilled in the art upon consideration of the present disclosure in its entirety.